Developer power replenishment means



United States Patent [72] Inventors Ira M. Sage New York, New York;

Peter P. Pungitore, Bronx, New York;

Peter J. Totino, Edgewater, New Jersey [21] Appl. No. 716,246 [22] FiledDec. 20, 1967 [45] Patented Aug. 11, 1970 division of Ser. No. 412,729,Filed Nov. 20,

1964, now Patent No. 3,385,161. [73] Assignee Old Town CorporationBrooklyn, New York a Corp. of New York [54] DEVELOPER POWERREPLENISHMENT MEANS 10 Claims, 20 Drawing Figs.

[52] U.S.Cl 118/637, 222/169 [56] References Cited UNITED STATES PATENTS2,732,775 1/1956 Young et a1. 1l8/637UX 2,757,635 8/1956 Lipsius 118/3122,761,416 9/1956 Carlson 118/637 2,904,000 9/1959 Fisher et al. 1 18/6372,910,963 11/1959 Herman 118/637UX 2,972,323 2/1961 Limberger 118/6373,152,732 10/1964 Schulman etal. 222/169 Primary Examiner- Peter FeldmanAttorney-Curtis, Morris and Safford ABSTRACT: This invention is used ina reader-copier which enlarges microfilm images, displays them on aviewing screen, and makes dry electrostatic photocopies of the materialsviewed on the screen. Photoconductive oxide-coated copy paper is used,and a dry developer mixture of carrier particles andelectrostatically-attractable developer particles is used to developelectrostatic images on the paper. A developer powder replenishingcylinder is provided for replacing developer powder into the mixture ashis used. The replenishing cylinder is a throw-away cartridge with aplurality of longitudinally-disposed holes. A rotatable scraper isprovided to scrape the insides of the cylinder; the cylinder is rotatedslowly so that every time the holes come into proper position, ameasured amount of powder is dropped into the developer mixture. Meansis provided for mixing the powder with the developer mixture. Thismixing means comprises a flexible webbing which is formed into a beltwhich moves continuously through the developer mixture. The mixer webserves the additional function of conveying the developer mixture to arotating magnetic brush which applies the mixture to the copy paper.This feature of the invention is described in greater detail in theportion of the specification entitled Developer Unit," and is shown inFIGURES 9 and 10 of the drawings.

Patented Aug. 11(1970 3,523,518

Sheet 1 of 12 INVENTORS. IRA M- SAGE PETER P. PUNGITozE PETER J7 TOT'IHOPatented Aug. 11, 1970 Sheet INVENTORS: IRA M1 SAGE- PETER P. P NGITOREPETER JZTormo ciiziiigaaukjgz "1 BY ATT RNEY 7y Patented Aug. 11, 19703,523,518

Sheet 5 of 12 F/GI3.

lNVENTORS f IRA M. SAGE, PETER R PUNGITORE Q P TER J. TOTINO 1w WW -j vPatented Aug. 11, 1970 3,523,518

Sheet 4- 0112 Patented Aug. 11, 1970 4 3,523,518

Sheet 5 of-12 INVENTORS. nu M- SAGE Perea P- Pumnoae PETER a. TOTINOATTORNEY 5 Patented Aug. 11,1970 3,523,518

Sheet 6 of 12 INVENTOR5. IRA M. SAGE PETER. P. wumroze PETER JHTOTINO AORNEY Patented Aug. 11, 1970 Sheet 8 of 12 FIG/0.

WNVVVVUNMPF mvsmons: 12A

M- $AG-E PETER P. PuMGlToRE PETER J. TOTIN ATTORNEYS Patented Aug. 11,1970 Sheet FIG. /2.

INVENTORS. IRA M- SAGE PETER P. RI G/r0125 PETER J. ToTmo WF K WATTORNEYS Patented Aug. 11, 1970 Sheet FIG/6.

E a o wrm v T m wmm A N5PJ R w W m fim m an IPP Patented Aug. 11, 1970Sheet 1 of 12 INVENTOR S: IRA M. SAGE PETER- P. PONGH'ozE P TEIL J"- TTI b1 ATTORNEY DEVELOIER POWER REPLENISIIMENT MEANS This is a divisionof US. application Ser. No. 412,729, filed Nov. 20, 1964, now Pat. No.3,385,161.

This invention relates to apparatus for displaying and copyingdocuments; more particularly, this invention relates to apparatus forenlarging, displaying and copying documents recorded on microfilm.

It is an object of the present invention to provide, for use in suchequipment, novel brush apparatus for applying developer powder todevelop latent electrostatic images clearly and cleanly.

A further object of the present invention is to provide novel means forintroducing additional developer powder to the brush as the developerpowder supply is depleted.

A still further object of the present invention is to provide novelmeans for quickly and efficiently mixing such developer powder withcarrier particles used in applying the developer powder to the latentelectrostatic images.

It is another object of the present invention to provide novel means formaking electrostatic copies of stationary documents.

The drawings and description that follow describe the invention andindicate some of the ways in which it can be used.

In addition, some of the advantages provided by the invention will bepointed out.

In the drawings:

FIGURE 1 is a perspective view of a microfilm reader-copier made inaccordance with the present invention;

FIGURE 2 is a cross-sectional and partially schematic view taken alongline 2-2 of FIGURE 1;

FIGURE 3 is a perspective and partially schematic view of some of thecomponents of the apparatus shown in FIGURES land 2;

FIGURE 4 is a cross-sectional view taken along line 4-4 of FIGURE 2;

FIGURE 5 is a cross-sectional view taken along line 5-5 of FIGURE 4;

FIGURE 6 is a cross-sectional view taken along line 6-6 of FIGURE 4;

FIGURE 7 is a partly schematic detailed elevation view of some of thecomponents of the machine shown in FIGURES l and 2;

FIGURE 7A is a cross-sectional view taken along line 7A- 7A ofFIGURE 7;

FIGURE 8 is a schematic view of the drive arrangement used for actuatingthe developer mechanism of the apparatus shown in FIGURES l and 2;

FIGURE 9 is a cross-sectional, partially schematic view of the developermechanism of the present invention;

FIGURE 10 is a partially broken-away cross-sectional view taken alongline 10-10 of FIGURE 9;

FIGURE 1 l is a partially broken-away view taken along line 11-11ofFIGURE 9;

FIGURE 12 is a partially cross-sectional, partially schematic elevationview of a portion of the paper-cutting apparatus ofthe machine shown inFIGURES l and 2;

FIGURE 12A is a partially cross-sectional elevation view of anotherportion ofthe paper-cutting apparatus of the machine shown in FIGURES land 2;

FIGURE 13 is a partially cross-sectional, partially cut-away elevationview of the paper-cutting apparatus shown in FIGURE 12;

FIGURE 13A is an enlarged view 'of a portion of FIGURE 13;

FIGURE 14 is a cross-sectional view taken along line 14-14 ofFIGURE 13;

FIGURE 15 is a partially cross-sectional elevation view of apparatusforming a part of the machine shown in FIGURES l and 2;

FIGURE 16 is a cross-sectional view taken along line 16-16 ofFIGURE l5;and 7 FIGURE 17 is a schematic diagram of the electrical control circuitofthe machine shown in FIGURES l and 2.

OVERALL OPERATION The overall operation and performance of thereader-copier machine of the present invention now will be explainedwith reference to FIGURE 1. The reader-copier 20 is designed to be usedon top of a table with the operator seated in front of it. The operatorplaces a magazine 22 of microfilm 24 on a turntable 26 and threads themicrofilm 24 through a rotatable projector assembly 28 and onto atake-up reel 30 which also is mounted on the turntable 26.

The machine 20 is turned on by means of an on-off switch 32. This lightsthe projector lamp and displays an image of the microfilm document on aviewing screen 36. Then, the operator turns a microfilm alignment knob34 which causes the projector mechanism 28 and turntable 26 to rotate afull 360 to any desired position in order to align the image appearingon screen 36 in a vertical position regardless of the angle at which thedocument originally was recorded on the microfilm.

A scanning knob 37 is provided. It may be turned to move the microfilm24 through the projector apparatus 28 until the frame containing thedesired document appears on screen 36.

In accordance with the present invention, a horizontal editing bar 38 ispositioned on the inside surface of viewing screen 36. An editing knobor crank 40 is provided so that the operator may move the editing bar 38up and down screen 36. As will be decribed in greater detailhereinafter, apparatus is provided in the reader-copier 20 for copyingonly that portion of the image that appears on screen 36 above theediting bar 38. Thus, by turning editing crank 40, the operator mayselect a given section of the document for copying and is not forced tocopy the whole microfilm frame being viewed on screen 36.

When the operator has found the frame desired and-has positioned theediting bar 38, he may automatically print'the desired portion of thedocument merely by setting a rotary selector switch to obtain theexposure time desired (long or short exposure), and then pressingautomatic print button 44. In accordance with the present invention, theselected portion of the document will be printed automatically on acontinuous web of copy paper and the length of paper used in making thecopy will correspond directly to the distance from the upper edge ofediting bar 38 to the top of screen 36. r

lf manual control of the exposure time is desired, the selector switch42 is turned to the manual operation position, manual print button 46 ispushed and held in for the length of exposure time desired, and is thenreleased. The copying operation then will proceed automatically asdescribed above.

If desired, the above operation can be repeated immediately so as torecord a selected portion of another document closely adjacent to thecopy of the first document on the continuous web of copy paper. Thisfeature can be very advantageousin many operations such as those inwhich it is desired to make a single compact record of many differentshort microfilm entries. This can give very significant savings incopy-making time, in copy paper costs, and gives a very compact copywhich is easy to use.

When a desired record has been completed, it may be cut off by pressingrocker-type switch 48 upwardly. As further copy-making proceeds, the cutcopy will emerge from the rear of the machine 20 and will be depositedin a hopper 50 at the rear of the machine. If it is desired to obtainthe cut copy immediately, rocker switch 48 may be pressed downwardly andthe cut copy will be fed into hopper 50 immediately. I

Novel means are provided for identifying each copy-made by thereader-copier machine. When desired, a serial number is automaticallyprinted at the beginning or end of a given copy. This may beaccomplished merely by moving edit bar 38 close to the top of screen 36,setting selector switch 42 to the automatic numbering" position, andthen pressing the automatic print button 44. The number will be printedon a short length of copy paper either preceding or following the copyto be identified with the number. The serial number may be increased onedigit by pressing rocker switch 52 downwardly, and may be displayed atthe lower edge of screen 36 by pressing rocker switch 52 upwardly. Thenumber is similarly displayed while being copied.

A reset switch 53 is provided to reset the copying apparatus in case ofmalfunction.

EDITING SYSTEM The system for producing edited copies of the displayeddocument is illustrated in FIGURES 2 through 6. Referring now to FIGURES2 and 3, and especially to FIGURE 3, editing bar 38 is clamped at itsends to a pair of chains 54 and 56 by means of clamps 58. Drive chain 54is driven upwardly and downwardly along the edge of screen 36 by asprocket 60 which is driven by bevel gears 62 and 64, the latter ofwhich is coupled to editing knob 40 by means of a sleeve 66 (see FIGURE2).

It should be noted that sleeve 66 rotates independently from shaft 68 towhich microfilm alignment knob 34 is secured. Shaft 68 drives bevelgears 70 and 72 which, in turn, drive bevel gear 74 which mates withring bevel gear 76 to rotate the projector assembly 28 and the turntable24 to align the microfilm in the machine.

Referring again to FIGURE 3, drive chain 54 passes over an idlersprocket 78 and a sprocket 80 at the top of screen 36 which is mountedon a shaft 82 which extends along the top of screen 36 and has asprocket 84 secured to its other end. Editing bar drive chain 56 isdriven up and down by sprocket 84 and passes over an idler sprocket 86at ,the bottom of screen Drive chain 54 passes over another idlersprocket 88 and then over sprocket 90 which is attached to the end of ashaft 92 which is located at the upper end of a printing screen 94 overwhich the copy paper passes and upon which the paper is charged andexposed.

Secured to shaft 92 are mask drive sprockets 96 and 98 which drive maskchains 100 and 102, respectively, which are used to position a maskwhich will be described below. Chains 100 and 102 pass around idlerpulleys 104 and 106, respectively, which are rotatably mounted on ashaft 108 located at the lower end of printing screen 94. Two sprockets110 and 112 are secured to shaft 108 and drive charger chains 114 and116, respectively. Chains 114 and 116 idle upon sprockets 118 and 120,respectively, which are rotatably mounted on shaft 92.

Referring now to FIGURE 4 as well as FIGURE 3, a corona charging unit122 is provided for applying an electrostatic charge to the oxide-coatedsurface of electrostatically-sensitive copying paper 124 (see FIGURE 2)which is fed from a roll 126 and which moves along the underside ofprint screen 94.

As is shown in FIGURES 3 and 4, corona charger 122 is suspended beneathprint screen 94 on a pair ofguide members 128 and 130. Members 128 and130 are fitted into guide slots extending longitudinally along printscreen 94 with the edges of the guide slot fitted into grooves 132 and134 in the members 128 and 130. Members 128 and 130 are clamped tocharger chains 116 and 114, respectively, by means of clamps 136 and138.

Referring now to FIGURE 3, a mask 140 is provided for covering theportion of the copy paper 124 on print screen 94 which is not needed forcopying the image portion above edit bar 38. Mask 140 is moved up anddown print screen 94 by the turning of edit knob 40 and thus moves incorrelation with the edit bar 38.

Mask 140 preferably is an opaque window shade which is spring-wound in aroll in a housing 142. its leading edge is secured to a bar 144 which isfastened at its ends to guide members 146 and 148, each of which slidesin one of the same slots 131 as do members 128 and 130. Guide member 146is clamped to mask chain 102, and guide member 148 is clamped to maskchain 100.

A spring detent arrangement is provided between charger 122 and mask 140so that the charger is releasably secured to mask 140 and follows itwherever it moves until the charger is driven away form the mask. Thus,turning the editing knob 40 has the following results: drive chain 54 isdriven, editing bar 5 38 moves upwardly, and chain 54 drives shaft 92.This causes mask chains 100 and 102 to move the mask 140 from the lowerposition shown in FIGURE 2 to the position shown in FIGURE 3corresponding to the position of edit bar 38 on screen 36. Mask 140 issecured by detents to charger 122 and carries the charger upwardly withit. Charger 122 is free to move with mask 140 since its chains 114 and116 idle on shafts 92, and since at this time shaft 108 is free torotate.

When the operator presses the print button to print the unmasked portionof the copy paper at printing screen 94, a brake 150 (FIGURE 3) isactuated to lock shaft 92 and screen 140 in position. Also, a clutch 152is engaged to couple a shaft 154 to shaft 108.

As is shown in FIGURE 2, shaft 154 is driven through sprocket 156 andchain 158 by the main drive motor 160 of the reader-copier 20. Theengagement of clutch 152 causes driven shaft 154 to drive shaft 108 andmove charger 122 upwardly and away from mask 140. Corona charger 122moves upwardly across the unmasked copy paper and applies anelectrostatic charge to it in a manner well known in the art. Whencharger 122 reaches the uppermost end of its travel it strikes a limitswitch which deactivates clutch 152 and energizes another clutch 162which now causes shaft 154 to drive shaft 108 in the opposite directionand return charger 122 to the forward edge of mask 140 where it is againlocked in position. At that point the charger strikes another limitswitch which de-energizes clutch 162 and releases shaft 108. Clutches152 and 162 are of standard design. Clutch 152 causes shaft 108 to bedriven in one direction by means of a toothed belt 164, while clutch 162causes shaft 108 to be driven in the opposite direction by means ofagear train 166.

In another embodiment of the invention, charger 122 makes only onecharging pass over the copy paper and is not locked to mask 140.instead, it normally rests at the top of screen 94 and makes itscharging pass downwardly. It stops when it hits switches at the leadingedge of the mask 140, and returns to the top of screen 94 after the copyhas been completed.

In both of the above-described embodiments, the speed of copying processis considerably increased because the charger need pass over only thatportion of the copy paper to be used in copying. The latter of the twocharger-movement embodi ments produces even faster copying since onlyone charging pass is used. 50

OPTICAL SYSTEM Referring now to FIGURE 2, when the microfilm is beingviewed on screen 36, the document image is projected from the lensbarrel 168 of projector assembly 28 onto a mirror 170 and is thenreflected along dashed lines 172 to the screen 36. Mirror 170 is mountedon a plate 174 hinged along its upper edge to a shield plate 176 of thereader-copier machine 20. When the print button 44 on the front of themachine is pushed, an electric motor (not shown in FIGURE 2) rotates ashaft 178 which is attached to a lever arrangement 180 to swing theplate 174 towards the front of the machine until it reaches the positionshown by dashed lines 182. Thus, mirror 170 no longer blocks the imagefrom reaching the printing screen 94. However, as plate 174 starts toswing forward, the projector lamp is turned off so that the documentimage is not projected on screen 94.

The projector lamp remains turned off while the charging operationdescribed above is taking place. After the charger has completed itswork, the projector lamp is turned on again and a document image isprojected upon the copy paper at printing screen 94. The portion of thepaper which is covered by mask 140 and charger 122 is not exposed. Afterthe copy paper has been exposed for a suflicient length oftime (as willbe explained in greater detail below), the projector lamp is againturned off, plate 174 is swung back to its initial position,

and the paper feed assembly 184 shown in FIGURES 3 through 6 is actuatedto cause the latent image-bearing copy paper to move upwardly past adeveloper unit 186 to develop the latent image, past a'fuser 276 whichfuses the thermoplastic developer powder into the copy paper, through apaper cutter 280, and out of the machine.

PAPER FEEDING AND LENGTH CONTROL SYSTEM FIGURES 4 through 6 show thedetails of the paper feed control assembly 184 which is shownschematically in FIGURE 3. It should be noted that, for the sake ofclarity, control assembly 184 is shown in FIGURE 4 raised from itsactual position, which can best be seen in FIGURE 3.

Control assembly 184 includes an input drive gear 188 which meshes witha smaller gear 190 which is secured to shaft 154. Gear 188 is driven bygear 190 whenever drive motor 160 is energized, and is rotatably mountedon a shaft 192 by means of a single-revolution Tiny clutch 194. Clutch194 has a tab 200 which is normally engaged by a pawl 198 to disengagethe clutch. However, after the exposure step is completed, solenoid 196(see FIGURE 6) is energized and pulls pawl 198 away from the tab 200 toengage the clutch and couple gear 188 to shaft 192. After releasing thetab 200, the solenoid 196 is de-energized, and a spring 202 returns pawl198 to its initial position so as to engage the tab 200 when it returnsto its initial position.

Two identical cams 204 and 206 are secured to shaft 192. As it rotates,the tip of cam 204 closes first one and then the other ofa pairofmicro-switches 208 and 210 which are firmly fixed in the positionshown in FIGURE 4. The tip of cam 206 similarly closes two othermicro-switches 212 and 214 which are mounted on a rotatable mountingpanel 216 (see FIGURE 5). As will be described in greater detail below,switches 208, 210,212 and 214 are used in timing the operation of thepaper feed apparatus and other components of the copying system.

Mounting panel 216 is secured to a paper length-metering sprocket 218 bymeans of a hub 220. Sprocket 218 is coupled to a smaller sprocket 222 bymeans of a chain 224 (see FIGURE 3). Sprocket 222 is rigidly attached tomask sprocket 104, and both sprockets 104 and 222 are mounted to rotatefreely on shaft 108. Thus, as seen in FIGURE 5, sprocket 218 and panel216 are rotated counter-clockwise by upward movement of the mask 140 soas to reduce the elapsed time taken by cam 206 to rotate clockwise fromthe initial position shown to the position in which it closes switch212. Since the closing of switch 212 stops the paper feed, thispositioning of panel 16 controls the length of paper which is fed sothat it corresponds to the amount of copy paper left unmasked by mask140.

When shaft 192 first is rotated by gear 188, cam 204 closes switch 208which actuates a paper feed clutch (not shown) on main drive motor 160.Motor 160 then starts driving a pair of paper feed rollers 228 by meansof a chain 226. Another chain 230 connects the drive of rollers 228 toanother pair of feed rollers 232 near the top of the reader-copiermachine 20. When cam 206 closes switch 214, the paper feed clutch isdisengaged and the paper feeding stops. A brake 234 is connected toshaft 192 in order to stop shaft 92 quickly after it has been releasedby the clutch 194.

DEVELOPER UNIT ADVANCE AND RETRACT APPARATUS Just prior to the start ofthe paper feed, the developer unit 186 is moved from the position shownin FIGURE 2 to the position shown in FIGURE 9; that is, it is advancedfrom its normal position in which its toner-applicator brush member 234does not contact the paper 124, to position where brush member 234contacts the paper. Then, after the paper has stopped feeding, thedeveloper unit 186 is retracted to its normal position.

This feature is highly advantageous in that the brush member does notremain in contact with the stationary copy paper between the making ofsuccessiye copies and, hence, will not cause large over-developeddarkened areas that otherwise might occur. In addition, the retractionof unit 186 allows the microfilm image to be projected up to a higherpoint on the copy paper at printing screen 94, thus allowing the spacingbetween adjacent copies on the continuous web of copy paper to beminimized.

The details of the mechanism 236 used for retracting and advancing thedeveloper unit 186 are shown in FIGURES 7 and 7A. Developer unit 186 ismounted on a channel member 237 on a carriage 238 which slides back andforth on a pair of rollers 239. The carriage 238 has a pair of toothedracks 240 each of which mates with the teeth of a gear sector 242. Eachof a pair of cams 244 is secured to a shaft 246 and is pivotallyconnected to one sector 242 by a connecting member 247 which isrotatably mounted on cam 244 by a bearing 245. A Tiny clutch 248 ismounted on shaft 246 and is engageable to couple a sprocket 250 to shaft246. Sprocket 250 is driven by main drive motor through by a chain 252(see FIGURE 2).

The engagement of clutch 248 is controlled by a pair of pawls 254, 256which alternately engage the tab 258 of clutch 248 to disengage it. Asolenoid 260 has a plunger 262 connected to a bar 264 to which the pawls254 and 256 are pivoted at their mid-sections. Pawls 254 and 256 arepivoted at one end to the machine frame by pivot pins 266 and 268,respectively. A post 270 serves as a stop to limit the upward motion ofpawl 256. A spring 272 normally pulls bar 264 up-to its uppermostposition. In this uppermost position, pawl 256 engages tab 258 of clutch248 and maintains the developer unit 186 in its normal position awayfrom the paper. When solenoid 260 is energized, bar 264 is pulled down,releasing the tab 258 of clutch 248 and bringing pawl 254 downwardly toengage tab 258 and disengage the clutch when tab 258 reaches theposition shown in FIGURES 7 and 7A. This engages clutch 248 for onehalf-revolution, driving cams 244 and causing sectors 242 to rotateclockwise and advance developer unit 186 to the copy paper.

When the paper stops feeding, the solenoid 260 is de-energized and thetab 258 is allowed to rotate another half-revolution around to itsinitial position. This causes gear sectors 242 to rotatecounter-clockwise and retract developer unit 186. Thus, cams 244 havebeen driven one complete revolution in two equal steps, the first stepmoving the developer unit forward and the second returning it to itsinitial position.

DEVELOPER UNIT Referring now to FIGURES 2 and 8, the developer unit 186is operated by a drive motor 282 and a chain 284 which is connected to asprocket 286 (see FIGURE 11) mounted on a shaft 288. Brush member 234 isdriven by means ofa sprocket 290 secured to shaft 288, another sprocket292 secured to a shaft 294 forming a part of brush member 234, and achain 296 connecting sprockets 290 and 292.

Referring now to FIGURE 9, developer unit 186 includes a housing 298which is secured to channel member 237. A quantity 300 of developermixture is maintained in the housing 298 and is continuously supplied tobrush member 234 by a mixing and feeding web 312 which will be describedin greater detail below.

The developer mixture is conventional, and comprises, for example, ironpowder particles mixed with relatively smaller particles ofthermoplastic pigment material. This pigmentor toner powder is of thereversal type; that is, of a'type which is attracted to uncharged areasand repelled from charged areas of the copy sheet. The use of this typeof toner is required because the microfilm document images arenegative," and it is desired to make positive" copies of them.

The brush member 234 is made of ferromagnetic material and is magnetizedin a conventional manner by a permanent magnet structure 302. Theforward face 304 of permanent magnet structure 302 is spaced from thepaper backing plate 306 so that there is room for the magnetic structure302 to retract with the developer unit 186 as it moved away from thepaper 124. As is well known, the iron powder particles in the developermixture 300 will form bristles on the surface of brush member 234, andthese bristles will brush against the paper 124 and will give up thedeveloper powder particles to the latent electrostatic image on the copypaper 124.

In accordance with one aspect of the present invention, a section 308 ofdeveloper backing plate 306 is recessed so as to form a depression inthe plate 306 at the position where brush member 234 approaches it. Whenthe developer unit 186 is advanced, brush member 234 is moved into thedepression so that the paper 124 is bent inwardly and makes intimatecontact over an area of brush member 234 which is greater than it wouldbe if the paper were flat. This improves the quality of the copyproduced.

As the brush 234 rotates past the paper 124, the tonerdepleted developermixture remaining on the brush surface is scraped off by a scraper 310which guides the mixture onto the moving mixing web 312 which carriesthe depleted developer mixture rcarwardly in housing 298, mixes it withany new toner powder that may be added at that point, stirs it into thebody of mixture 300 in the housing 298, and pushes mixture body 300toward the brush member 234.

Referring now to FIGURE 10, developer web 312 comprises a number ofcircular rubber rings 314 each of which is looped around two parallelshafts 316 and 318. Each ring 314 is fastened to the next ring by metalclips 320. Each ring is fastened to the ring on one side at two pointsapproximately 180 apart on the ring and is fastened to the ring on theother side at two points also 180 apart and 90 from the first fasteningpoints. This network is stretched over shafts 316 and 318 and forms aseries of interlaced diamond-shaped scoops which effectively mix thedeveloper mixture. A number of parallel rings are fastened together andwound around the ends of shafts 316 and 318. These rings are held inplace by a flange 324 near each end of each shaft. This structure holdsthe ends of web 312 and prevents slipping of the web ends towards itsmiddle.

Referring now to FIGURES 8 and I], shafts 316 and 318 are driven at aspeed around one-third of that of brush 234 by means of a sprocket 328secured to shaft 288, a chain 330 driving a larger speed-reducingsprocket 332 which drives a smaller sprocket 334. Sprocket 334 iscoupled to sprockets 338 and 340 on shafts 316 and 318, respectively, bymeans of a chain 336. Another sprocket 342 on shaft 318 is connected bymeans of chain 344 to a large sprocket 348 which drives a shaft 350 atabout one-ninth the speed of brush 234 for actuating the toner-addingapparatus, to be described below.

The mixer web 312 is extremely effective in quickly mixing developer andcarrier particles and in feeding the mixture to the brush. in fact, ithas been found that one revolution of the webbing usually is sufficientto thoroughly mix a moderate quantity of fresh toner powder into thedeveloper mixture. As a result, shafts 316 and 318 can be and are turnedat a speed substantially lower than that of brush 234. The resultofthis, it is believed, is that there is less fatigue' of the ironpowder particles; that is, the iron powder particles do not readily losetheir ability to pick up and carry toner powder particles and rarely,ifever, need replacing.

Referring now to FIGURE 1 l, a toner-supply cartridge 356 is rotatablymounted in a generally tubular portion 386 of the developer housing.Toner-cartridge 356 is of the throw-away type designed to be used,thrown away, and replaced with another. Cartridge 356 includes a tube358 preferably made of paper-board, plastic, or other inexpensivematerial, a pair of plastic end caps 357, and a metallic scraper 362. Asis shown in FIGURE 1 I scraper 362 has a square cross-sectional shapeand is bent in the form ofa bail so as to scrape against the insidesurface of the cylinder. Cylinder 358 has a row of holes 364 along oneside.

A cover assembly 366 is provided to seal the toner cartridge 356 intothe developer unit. Cover assembly 366 includes a knob 368 with a shaft370 secured to and extending inwardly from knob 368. A bushing 372 issecured to shaft 370, and a bearing 374 is secured to bushing 372. Anadapter 360 is rotatably mounted on bearing 374, and a circular spring376 abuts the flanged surface of bearing 374 and the inward surface ofknob 366 to thrust the cartridge 356 into the housing 386. The inwardend 378 of shaft 370 is slotted to mate with and hold the square-shapedend 380 of scraper and prevent it from rotating. A bayonet pin 382 locksinto a slot 384 in housing 386 to hold the cover assembly 366 securelyin place.

Toner cartridge drive shaft 350 has a hollow end 352 to which isfastened an adapter 354 which couples a drive spring 351 to the shaft.The ends of spring 351 extend beyond the periphery of adapter 354 andfit into slots 355 in the edge of cartridge 356. Spring 351 is drivablyconnected to adapter 354 by means of tabs 359 which fit into slots 361in the adapter.

Hollow end 352 of shaft 350 fits loosely around end 353 of scraper 362so as to allow the scraper to remain stationary while the cartridgerotates. Adapter 354 fits loosely into the end cavity of the cartridge;the drive coupling to the cartridge is made through spring 351 and slots355.

Toner cartridge 356 provides an extremely convenient way of replenishingdeveloper powder in the developer mixture 300. The cartridge is rotatedslowly by shaft 350 while the scraper 362 remains stationary. Every timethe row of holes 364 comes adjacent the mixer web 312, a small incrementof toner powder is dropped into the web. Web 312 quickly mixes thistoner powder with the developer mixture 300 and rubs the carrier andtoner particles together to create triboelectric attraction betweenthem. The stationary scraper scrapes the insides of cylinder 356 andprevents holes 364 from becoming clogged.

Toner cylinder 356 is extremely clean to use since a piece of masking orcellophane tape can be placed over the holes 364 until the cartridge isto be used. When it is desired to replace an empty cartridge, the knob368 is turned and the cover as sembly 366 is removed. The old cartridgeis withdrawn from the housing and thrown away. The tape is stripped offof the holes 364 in the new cartridge, and the new cartridge is insertedinto the housing 386. Then the cover assembly 366 is replaced.Advantageously, the new cartridge need not be aligned by the operator inorder to connect it to the drive shaft 350.1fthe ends of spring 351 arenot initially aligned with the slots 355, the spring ends will flexinwardly and then will snap into the slots as the spring rotates.

Thus, the toner supply for the copying machine has been changedeffortlessly and cleanly. This is to be compared with conventionalmanner of adding toner in which fine black powder is poured from acontainer into a hopper. This con ventional procedure spreads toner dustover the machine and its operator.

Referring now to FIGURE 10, the surface of brush 234 can be knurled torender it effective to form iron-particle bristles. but is preferablyroughly sand-blasted to achieve this effect. Sand-blasting is lessexpensive than knurling and produces an excellent brush-bristle formingsurface.

Developer unit 186 is easily removable from the reader-copier machine20. It is mounted on channel member 237 which slides onto a supportmember 388 (see FIGURE 9). As is shown in FIGURE 10, a lock-handle 390is turned to move a lockplate 392 to the position shown in dashed linesto cover the end of channel member 237 and lock the developer unit 186in place.

PAPER-CUTTING SYSTEM Solenoid 400 lifts plunger 396 upwardly quicklywhen energized in response to the actuation of switch 48. A notch is cutout of the edge of the paper by shearing between the edge 401 of theplunger 396 and a cutting edge of a metal cutting member 402. A spring404 returns the plunger 396 downward quickly after switch 48 isreleased. The notching unit 394 is positioned on the upper portion ofscreen plate 94 so that the notch is cut in the copy sheet at the end ofa copy.

The paper-cutting assembly 280 is shown in FIGURE 12. As the paper 124passes around a guide 278, an arm 406 of a feeler switch 408 dropsdownwardly into the notch in the edge of the paper. This actuates asolenoid 410 which swings a pawl 412 out of engagement with the tab 414of a Tiny clutch 416 (see FIGURE 13 Pawl 412 is pivoted on a pivot 413,and is urged into engagement with tab 414 by a spring 415. A stop member417 limits the movement of pawl 412. As is shown in FIGURE 13, therelease of tab 414 causes clutch 416 to engage and couple a sprocket 418to a shaft 420 forming a part of a knife unit 422. Sprocket 418 isdriven by roller shaft 424 (see FIGURE 12) by means ofa chain 426.

Referring now to FIGURES 12 through 14, knife unit 422 includes a pairof parallel rotatably-mounted shafts 420 and 428. An upper cutting bladeis mounted in a cut-out portion of shaft 428 by means of a pair ofscrews 432 and 434. A lower cutting blade 436 similarly is mounted-in acutout portion of shaft 420 by means of screws 438 and 440. Each cuttingblade is slightly wider at the right end (as shown in FIGURE 13) than atthe left end. Also, the mounting surface for each blade at its left endis inclined with respect to the mounting surface at its right end sothat each blade is given a helical twist, lower blade 436 being twistedclockwise as viewed in the direction of arrows 14, and upper blade 430being twisted counterclockwise. Lower blade 436 has anoutwardly-extending lobe 442 at its left end beyond its cutting edge.Similarly, upper blade 430 has an outwardly-extending lobe 444 at itsright end beyond its cutting edge. A beveled cut-out portion 446 isprovided at the left end of upper blade 430 to mate with lobe 442.

When sprocket 418 is clutched to shaft 420 in the manner describedabove, shafts 420 and 428 are rotated for one revolution in oppositedirections, thus bringing the cutting edges of blades 430 and 436together in a sweeping shearing motion; that is, in a shearing motionthat takes place while the blades are sweeping" or moving with thepaper.

Shaft 428 is rotated by means of a spur gear 448 secured to shaft 420and mating with another spur gear 450 which is coupled to shaft 428 bymeans ofa spring-coupling indicated generally at 452 in FIGURE I 3 andillustrated in greater detail in FIGURES l3A and 14. Spring coupling 452includes three flat springs 454, 456 and 458, each of which is coiledinto a spiral at both ends. One end of each coil spring is wound arounda post 460, 462 or 464, respectively, which is mounted upon spur gear450. The other end of each spring is coiled around a post 466, 468 or470, respectively, which is secured to shaft 428 by means of an annularmember 472. As is best shown in FIGURE 13A, the right end 474 of pin 462fits into a slot 476 in shaft 428. There is substantial room for pin end474 to move circumferentially within slot 476, thus giving considerableplay" between gear 450 and shaft 428. The three springs 454, 456 and 458urge the cutting edges of blades 430 and 436 together to ensure cleanpaper-cutting, but, because of their flexibility, do not cause theblades to bind together or wear excessively.

The knife unit 422 is highly advantageous for cutting a moving paperweb. The shearing action is created by the rotation of two shafts whichare driven by the same drive system which feeds the paper through theunit. Thus, the shearing blades move or sweep along with the paper asthey are cutting it and thereby prevent the paper from gathering infolds and clogging in the cutting assembly 280. What is more, the knifeblades sweep the cut copy as they move along and eject it from themachine, thus avoiding the necessity of providing an additional set ofdrive rollers. Furthermore, the lobes 442 and 444 which make initial andfinal contact between the blades, and

SERIAL-NUMBERING SYSTEM FIGURES 15 and 16 show a serial-numberingassembly 478 which is used to place an identifying serial number oncopies made in the reader-copier 20. Numbering assembly 478 is not shownin FIGURE 2 because of lack of room in that FIGURE.

Numbering assembly 478 includes a first housing 480 and a second housing482 which are mounted in reader-copier 20 by means of support structureindicated at 484. A light shield 486 is mounted on the rear surface ofsupport 174 for mirror 170.

Referring now to FIGURE 16 as well as FIGURE 15, a Veeder-Root" counter488 is mounted in housing 480 with a pair of lamps 490 mounted at itssides. Light from the lamps illuminates the number appearing on the faceof the counter 488, and the image of the number is reflected outwardlyto a baffle plate 492 in housing 482. Baffle plate 492 has a mirror 494and an opening 496. Mirror 494 reflects the image upwardly and opening496 allows the image to pass straight through a lens 498 in a tube 500which projects through a hole in the lower shield 502 of thereader-copier 20. The number image passes through an opening 504 in theend of tube 500. an opening 506 in shield 508, and is displayed uponviewing screen 36. I

When swingable mirror support 174 is in the position show in FIGURE 15,the number image is reflected upwardly by mirror 494, passes throughlens barrel 486 and lens 510, and is projected upon copy sheet 124 atprinting screen 94. In this manner, the image of the number appearing onthe counter 488 is projected simultaneously on viewing screen 36 andcopy sheet 124 to be printed. When plate 174 is in its rearmostposition, the number image does not reach copy paper 124.

ELECTRICAL CONTROL CIRCUIT The electrical control circuit for thereader-copier 20 is indicated at 512 in FIGURE 17. The electricalcontrol switches are illustrated both in FIGURE 1 and in FIGURE 17. Theway in which the switches are used was related above in the initial partof this description. The operation of control circuit 512 now will beexplained by describing what happens when each control switch isactuated by the operator.

PUSHING ON-OFF SWITCH 32 TO TURN THE MACHINE Standard alternatingcurrent is applied to input terminals 514 and 516. When on-off switch 32is pushed to the on position, the following takes place:

1. Full-wave rectifier 518 is energized. It supplies direct current tothe various relays and solenoids of the circuit.

2. The projector lamp 520 is energized through switch 522, variableresistor 524, and a power relay 526. Switch 522 is located on mirrorsupport plate 174 (FIGURE 2) and is normally closed when the plate 174is in its rear-most position. Variable resistor 524 is used to .vary thevoltage applied to the projector lamp.

3. Fuser blower motor 528 is energized through a relay 590. Motor 528drives a blower which blows cooling air over the fuser to prevent itfrom overheating. A thermostat 530 senses the temperature near the fuserand energizes blower motor 528 whenever the blower is not energized andthe fuser gets too hot. i

4. Blower motor 532 is energized to drive the blower which cools theprojector lamp 520. I

5. Solenoid 534 (see FIGURE 2) which is used to automatically focus thelens in the projector assembly 28 on the screen 36.

6. A stepping switch 536 having ten levels, 537 through 546, ispositioned at its zero or starting position. Stepping switch llll 536provides the switching between various steps or functions of theautomatic and manual copying processes.

PUSI-IING SWITCH 52 TO VIEW OR ADVANCE THE SERIAL NUMBER When rockerswitch 52 is pressed upwardly to view the number appearing on theVeeder-Root counter 488 (FIGURES and 16), counter illumination lamps 490are energized through a step-down transformer 548 and a relay 550. Thisprojects an image of the counter number on the lower portion of theviewing screen 36.

Pushing switch 52 downwardly (FIGURE 1) energizes a solenoid 552 whichadvances the count on counter 488 by one number.

PRESSING AUTOMATIC PRINT SWITCH 44 TO MAKE A COPY When the masking bar38 has been positioned to mark the portion ofthe document to be copied,the operator presses the automatic print switch 44 to make a copy. Thisadvances the contact arm of each level of stepping switch 536 to thenext contact to the right (hereinafter referred to as the firstcontact). This stopping is performed by a coil 549 protected by a sparkprotector 551. This gives the following results:

(a). With stopping switch 536 in the first position:

1. The focusing solenoid 534 is de-energized.

2. Mirror motor 554 is energized and starts moving the projection mirror170 forward. This causes switch 522 to open.

3. Projection lamp 520 is de-energized when switch 522 opens.

4. Mask brake 150 (see FIGURE 3) is energized to lock the mask 140 inposition.

5. When the mirror 170 reaches its forward position, it closes a switch556 which causes the contacts of stepping switch 536 to be advanced tothe secton position.

(b). With switch 536 in its second position:

1. Mirror motor 554 is de-energized.

2. Relay 558 is energized, and in turn supplies main drive motor 160(see FIGURE 2) with alternating current.

3. High-voltage supply 560 is energized; it supplies high voltage energyto the charger unit 122.

4. Charger clutch 162 (see FIGURE 3) is energized. Clutch I62 now movescharger 122 downwardly along print screen 94 in the arrangementdescribed above in which only a single pass the charger is used tocharge the copy paper.

5. Switch 562 is located at the front edge of mask 140. It is closedwhen it is hit by charger 122 when it reaches the end of its chargingpass. This moves the contact arms of stepping switch 536 to the thirdpositron.

(c). With switch 536 in its third position:

. The following are de-energized: relay 558 and main drive motor 160;high voltage source 560; and fuser blower motor 528.

2. When the four-position selector switch 42 (FIGURE l) is in the"automatic numbering position both of its contacts 562, 564 contact thefirst (farthest left) contact. In this position, relay 550 is energizedthrough contact arm 564 and serial-numbering lamps 490 are lighted toproject a serial number onto the copy paper. Also, an electrical signalis sent through contact arm 562 and variable resistor 566 to aconventional timing circuit 568 which actuates a relay 570 after thecopy paper has been exposed to the number image for an exposure timewhich is set by variable resistor 566. The closing of the contacts ofrelay 570 then move the contact arms of stepping switch 536 to thefourth position.

3. With the contact arms 562 and 564 of reflector switch Photocell 576is an element ofa standard densitometer arrangement for automaticallysensing and timing the exposure required. The exposure time also iscontrolled by the resistance setting of variable resistors 572 and 574.After the copy paper has been exposed to the document image for theproper length of time, relay 570 is energized and the stepping switch536 is moved to its fourth position.

(d). With switch 536 in its fourth position:

1. The following are tie-energized. relays 570 and 550,

and, if they are energized, numbering lamps 490.

2. Developer unit advance solenoid 260 (see FIGURE 7) is energized tomove the developer unit into contact with the copy paper.

3. Relay 558 and main drive motor 160 are energized. 4. The movement ofdeveloper unit 186 towards the copy paper closes switches 578 and 580and opens switches 582 and 584. When switch 580 is closed an electricalsignal is sent through a fuser warmup timing arrangement which consistsof a variable resistor 586, a thermistor 588 and timing circuit 568. Thesimultaneous closing of switch 578 actuates a power relay 590 andenergizes the twin heating elements 592 of the fuser 276 (see FIGURE 2)to start it warming up to a proper fusing temperature. Thermistor 588senses the temperature of fuser elements 592 and, together with variableresistor 586 and timing circuit 568, controls the amount of time thefuser is allowed to warm up before paper is fed through it.

5. When the fuser has warmed up sufficiently. a signal is sent to relay570 which energizes solenoid 196 (see FIGURE 6) which releases the driveclutch for paperfeed control unit 184 (see FIGURE 4) and startspaper-length cams 204 and 206 rotating.

6. Cam 204 first closes switch 208 which moves the contact arms ofstepping switch 536 to the fifth position.

(e) With switch 536 in the fifth position:

1. Relay 570 and solenoid 196 are de-energized.

2. Paper feed clutch 594, located on main drive motor 3. Switch 212 isclosed by cam 206 after the cam has rotated at distance proportional tothe length of the paper copied. This moves stepping switch 536 to itssixth position.

(f). When switch 536 is in its sixth position:

1. Relay 590 and fuzer elements 592 are de-energized just before thepaper stops feeding.

2. Fuser blower motor 528 is energized to cool the fuser rapidly andprevent scorching of the copy paper next to it.

3. Switch 214 is closed by cam 206 (see FIGURE 5() to move steppingswitch 536 to its seventh position.

(g). With switch 536 in its seventh position:

1. Paper feed clutch 594 is de-energized and the paper stops feeding.

2. Mask brake 150 (see FIGURE 3) is de-energized to free the mask fromthe next copying operation.

3. Developer-advance solenoid 260 (see FIGURE 7) is de-energized andswitches 578 and 580 are opened, while switches 584 and 532 are closedby the retraction of developer unit 186 away from the copy paper. Also,relay 595 and developer drive motor are deenergized. The focusingsolenoid 534 is energized to refocus the microfilm image on the viewingscreen 36.

5. Mirror motor 532 is energized, returns the mirror 170 to its rearwardposition thus closing switch 522, de-energizing mirror motor 532, andenergizing the projection lamp 520, thus preparing the reader-copiermachine for viewing documents on viewing screen 36.

W o. Cam 204 (FIGURE 4) closes switch 210-which switches stepping switch536 to its eighth positio ni (h) With switch 536 in its eighth position,switch 584 is still closed and the switch 536 is stepped to its ninthposition.

(i) With switch 536 in its ninth position:

1. Charger clutch 152 (FIGURE 3) is energized to return the charger 122to the top of the printing screen 94.

2. When charger 122 reaches the top of print screen 94, it closes aswitch 596 which returns stepping switch 536 to its initial or zeroposition, thus preparing the control circuit for another copying cycle.

(j) When switch 536 returns to its zero position, relay 558 and maindrive motor 160 are de-energized, and a lamp 598 is energized toilluminate print button 44 from the inside to indicate to the operatorthat the machine is ready for another copying cycle.

PRESSING SWITCH 48 TO CUT OR FEED-OUT A COPY When rocker switch 48 ispushed upwardly to cut a copy after it is completed, this energizessolenoid 400 of notching unit 394 (FIGURE 12A) and notches the paper inthe manner described above. Note that solenoid 400 cannot be energizedunless stepping switch is at its zero position; that is, it cannot beenergized'when the copying apparatus is printing.

When the notch in the paper passes under arm 406 ofswitch 278 (FIGURE12), switch 278 closes and solenoid 410 is energized to actuate theknife unit 422 to cut the paper in the manner described above.

When switch 48 is pressed downwardly to feed a copy out of the machine,the paper feed clutch 594 on drive motor 160 is energized. Relay 590 andfuser elements 592 are energized, and current is supplied through thevariable resistor 600 to thermistor 588 to set the warm-up time of thefuser. After the required warm-up time, relay 570 is energized and inturn energizes relay 558 which starts the main drive motor to start thepaper feeding out of the machine. When the paper has been cut, or whenno more paper feed is desired, the operator releases switch 48 andde-energizes the drive motor, fuser and paper-feed clutch;

It should be understood that rocker switches 48, 52 and 53, and switches44 and 46, all shown in FIGURE 1 are closed only as long as they areheld in by the operator. Only on-off switch 32 and selector switch 42remain in position when released by the operator.

PRESSING RESET SWITCH 53 Reset switch 53 is pressed if, during aprinting cycle, the developer unit 186 is not in proper position, or ifthe paper length cams, charger, or stepping switch do not operateproperly and it is desired to start the printing cycle all over again.Pressing switch 53 energizes relay 602 which closes appropriate switchesto recycle the equipment and return the stepping switch 536 to itsinitial position.

The above description of the invention is intended to be illustrativeand not limiting. Various changes or modifications in the embodimentsdescribed may occur to those skilled in the art and these can be madewithout departing from the spirit or scope of the invention as set forthin the claims.

We claim: H

1. For use in an electrostatic copier utilizing a mixture ofelectrostatically-attractable pigment particles .and carrier particlesin developing latent electrostatic images, means for replacing pigmentparticles in said mixture as said pigment particles are used indeveloping copies, said replacing means comprising a containersubstantially completely sealed except for a plurality of dispensingholes in one side wall, means for mounting said container so as todeliver pigment particles to said mixture under the force of gravityeach time said dispensing holes are turned downwardly, and means forrotating said container through a complete revolution repeatedly, thusturning said dispensing holes downwardly periodically.

2. For use in an electrostatic copier utilizing a mixture ofelectrostatically-attractable pigment particles and carrier particles indeveloping latent electrostatic images, means for replacing pigmentparticles in said mixture as said pigment particles are used indeveloping copies, said replacing means comprising a containersubstantially completely sealed except for a plurality of dispensingholes in one side wall, means for mounting said container so as todeliver pigment particles to said mixture under the force of gravityeach time said dispensing holes are turned downwardly, said mountingmeans including a drive member for rotating said container through acomplete revolution repeatedly, thus turning said dispensing holesdownwardly periodically, spring coupling means for coupling said drivemember to one end of said container, and means for rotatably supportingthe other end of said container. I

3. Apparatus as in Claim 1 including a scraper member mounted in saidcontainer and adapted to be rotated with respect to said container andscraped over the internal surface of said container to keep said pigmentparticles flowing freely through said dispensing holes.

4. Apparatus as in Claim 3 in which said scraper member extendsoutwardly from said container, and means for gripping anoutwardly-extending portion of said scraper member and holding it toremain stationary while said container rotates.

5. A disposable toner powder storage and dispensing tube for use inreplacing toner powder depleted from a developer mixture during use ofsaid mixture in electrostatic copying; said powder tube being elongatedand cylindrical in shape and having a longitudinally-extending row ofdispensing holes in one side wall, at least one drive notch in at leastone end of said tube, a scraper member forming an integral part of saidtube, said scraper member comprising a length of wire with a squarecross-sectional shape, said wire being bent to have a central offsetportion and two ends, said scraper ends extending outwardly from saidtube through holes in the ends of said tube.

6. In combination with the toner powder tube recited in claim 5, agenerally tubular housing open at one end for lengthwise insertion ofsaid toner powder tube, a shaft at the other end of said housing, saidshaft having drivably coupled to it a longitudinally flexible memberadapted to be engaged in said drive notch, said shaft end having arecess for rotatably supporting said one end of said scraper member, acover member adapted to be thrust into said housing to close its openend, said cover member having a slotted member for engaging said otherend of said scraper member and securing'it against rotation.

7. For use in an electrostatic copier utilizing a mixture ofelectrostatically-attractable pigment particles and carrier particles indeveloping latent electrostatic images, a housing for containing saidmixture, means for mixing said mixture, said mixing means comprising websupport means rotatably mounted in said housing, a mixing web mounted onsaid sup port means, said mixing web comprising a plurality of rings offlexible material secured together on said support means and forming acontinuous web adapted to rotate with said support means, said supportmeans being positioned in said housing so that said web contacts saidmixture.

8. Apparatus as in Claim 7 in which each one of said rings is

